Abstract

This paper presents a design practice for the oil export pipeline (OEP) of Johan Sverdrup Oil Field subjected to unexploded ordnance (UXO) hazards during the pipeline installation period. The UXO (unexploded ordnance) is a potential risk to the oil export pipeline due to its significant impulsive pressure load in a short time. Present paper discusses an unfavorable scenario in which the UXOs are identified during the pre-lay survey stage. It may (and it does) happen due to the survey methods chosen between the initial preliminary and the pre-lay survey. Consequently the original design pipeline routing has to be updated in order to minimize the UXOs’ potential damage to the pipeline. A safety distance between pipeline and UXOs shall be established and maintained. To achieve this, advanced numerical simulation was used for assessing the damage of pipeline under UXO explosion loads. The damage is sensitive to the charge weight and the distance between charge and pipeline. The pipeline route was updated accordingly based on the safety distance and actual locations of UXOs. The new route shall also fulfill all design checks. With the updated pipeline routing, the installation could continue without interruption of the project schedule. The identified UXOs will be subject to later removal before startup of production to further ensure the safety of installed pipeline. The overall design process is presented. Some simulation results from Abaqus Explicit solver are shown in the paper. Conclusions and discussions are included, which may be useful for similar projects in the future.

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